HOW LONG TO LET ENGINE COOL BEFORE CHANGING OIL OF CAR?


Oil changing ensures your engine stays healthy, and performs its jobs optimally. However, utmost care must be applied when changing oil.

One of the crucial things to note when changing oil is the state of the engine since cars get hot when driven. Therefore, some drivers ask how long to let engine cool before changing oil? You should wait 20 to 30 minutes after a long drive before changing oil.

how long to let engine cool before changing oil

How long to let engine cool before changing oil?

If you’ve just driven your car, it’s important to let the engine sit between 20 to 30 minutes before changing oil. Oil temperature should be below 200 degree Fahrenheit. While this will not totally cool the engine, your engine will still be warm enough to allow you to change engine oil without inflicting injuries or taking much time.

It’s essential to allow it to cool as oil at this time will be hot, and if anyone spills and touches your skin, it will cause injuries. Even pouring oil into a hot engine can cause oil expansion, spillage and it can burn you. So if you’re asking how long does it take for engine oil to cool down, wait at least 20 – 30 minutes.

Should I let engine cool before changing oil

Yes, but don’t allow your engine to be completely cool. Likewise, don’t change the engine oil when the engine is also red hot. So how long does it take for oil to cool down?  If the car has just been driven, open your hood and allow the engine to cool for a while. At this point, the oil will still be warm enough to flow easily when being drained.

So for those asking, should I change oil hot or cold? It’s better to stay in the middle. If you let your engine cold, draining the oil will take longer and won’t even let out all the oil. Many oil experts recommend draining or adding oil to car when it’s hot for specific reasons.

First, a hot engine lets oil viscosity become thinner, so it drains faster than when the engine is cold. A hot engine will also let oil retain contaminants. Hence chances of pollutants leaving the engine when the oil is being drained are high. Again, a hot engine will let oil flow freely when new oil is added. You may also face smoke coming out of oil cap.

When experts say hot, not extremely hot engines, you may burn yourself from spillage. Another reason to avoid red-hot engines is other engine sections may still be hot, and you risk getting burnt if your body touches these parts. So while you don’t have to wait till it is completely cold, please don’t touch it when it’s too hot.

The Importance of the right temperature

Maintaining proper vehicle engine temperature is a critical aspect for smooth operation of car engine. A research by Alexander Khrulev of International Motor Bureau shares that “thermal damage to the cylinder head is possible within 10 seconds after the cooling failure”.

In addition, engines reach extremely high temperatures during operation, with components like the exhaust manifold becoming hot enough to cause severe burns. Apart from personal safety, attempting to change the oil when it’s too hot can lead to improper drainage, leaving residues that can impair engine performance. Conversely, letting the engine cool down entirely can make the oil too viscous, making it difficult to drain completely. Hence, aiming for a warm engine – not too hot, not too cold – is the golden rule for changing oil.

is it ok to put oil in a hot engine?

Can you put oil in a hot engine? Adding oil to a moderately hot engine is ok as hot engines usually make oil thinner allowing easy flow throughout the engine. If you haven’t driven for a while and the engine is cold, run the engine for 2 – 3 minutes, so it becomes warm enough to allow the free flow of oil. Cold oil takes a long time to circulate, and while draining, chances are not all the oil will come out.

However, while hot oil will flow quickly and easily, it can also cause burns. Thus, ensure the engine is not too hot. If just driven, let it cool for some time. How long after driving to change oil? Wait about 20 – 30 minutes.

Safety precautions while changing oil

While changing oil might look like a simple job, it requires utmost care, or you may inflict injury on yourself or waste time. If you are looking to cut money by performing your own oil change at home, follow the below oil change tips to successfully and safely carry out the job.

  • Don’t change oil when the engine is too hot to avoid burns. If you have recently driven your car, let it cool for 20 – 30 minutes before draining or adding oil.
  • If the engine is cold, allow it to run for 2 to 3 minutes. This allows the engine warm enough to allow free flow of oil but not hot enough to cause burns.
  • Wear rubber gloves and put towels close by to clean off spills that touch you quickly.
  • If the drain plug falls into the drain pan, don’t grab it immediately, as the pan might be too hot. Instead, wait a bit before retrieving the plug.
  • Securely drain the old oil into a drain pan to keep your workspace cleaned.
  • Oil filters can sometimes be difficult to remove, especially when you have oil in your hand. So, ensure you get an oil filter removal tool like the end cap style or clamp style wrenches.
  • Don’t litter the surrounding –whether garage or driveway. If you feel the job would get messy, spread an old curtain or tarp beneath your car. So, when you’re done, you can wipe and fold for another use.
  • Never leave oil seals dry as this can cause loose leaky filters to oil leaking on the ground. Instead, try spreading a little oil on the filter before installing it.
  • Use the manufacturer-recommended engine oil. Otherwise engine power will be reduced.
  • Pour in new oil using a funnel to enhance easy pouring and avoid spillage. And also, pour slowly to avoid overflowing the funnel
  • Don’t overfill your engine. Always consult your owner’s manual to know the right amount of oil recommended by your manufacturer. Then as you pour in, keep checking your dipstick, so you don’t overfill.
  • After you change engine oil, don’t forget to reinstall the drain oil plug and ensure it’s tightened correctly, about 25 lbs. If you feel the plug isn’t going in, check to see if it’s entering directly into the pan.
  • Dispose of the old oil appropriately by pouring it from the drain pan into a bottle

When to check engine oil level

Experts recommend checking your oil level at least once a month or before taking long trips. This helps you keep your oil at the right level, as running on extremely low oil can cause many problems. In addition, many recommend checking the oil level before putting on your engine or 5 – 10 minutes after putting off the engine. 

So if you’re asking, should I check oil levels cold or hot?  It’s better to check the oil level when the engine is cold so you don’t get burnt by hot engine parts. However, some automakers recommend doing this when the engine is warm–consult your owner’s manual.

check engine oil level

To check the oil level, park your car on leveled ground, pull out the oil dipstick and wipe it with a clean cloth. Then, reinsert the dipstick and see where the oil level is. The oil is on a good level if it’s between the upper and lower mark.

However, if it’s below the lower mark, top it but don’t overfill. You could also use this medium to check your oil condition. If it appears very dark and gritty, you may go for an oil change instead of adding new oil to an old one.

Conclusion

Car owners ask a common question, when it’s time to carry out an oil change is how long to let engine cool before changing oil. This article has, however, answered it, stating that one should let the engine cool for at least 20 – 30 minutes if the car was recently driven. This allows the engine to be warm enough for the oil to flow freely but not hot enough to cause burns.

When adding oil to car, also remember to wear rubber gloves and keep a towel close to you in case of oil spills on your hands. Lastly, while you want to avoid burn, an oil change is better done with warm engines. So if your engine is cold, allow it to run for about 2 – 3 minutes before draining or adding new oil, as it enhances the free flow of oil.

Shafiqule

Mr. Shafiqule Islam is a graduated Mechanical Engineer and has more than 15 years experience of repairing and maintenance of different brand vehicles like Toyota, Mitsubishi, Ford, Mercedes, BMW etc. He is also giving training to Mechanics. He has started writing to share his practical knowledge to Vehicle Owners, Drivers and Mechanics to keep their cars at best fit.

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